Striping machine

ABSTRACT

An electrostatic continuous printer having a stationary screen and powder supply and powder feed means respectively for supporting a supply of printing powder for transfer in a metered amount to said feed means, and for feeding the powder so transferred into an electrostatic field in an air gap disposed between the screen and the material to be printed upon for conducting the powder onto said material.

Ignited States Patent I 56] References Cited UNITED STATES PATENTS Marlin A. Sehueler Danville. Calif. 726.1 I I [72] inventor Appl. No. [22] Filed Londahl et al- 8/l967 Proskauer 3,338,161 8/1967 Owren...........

May 2,1968

[45] Patented June I, 197! [73] Assignee Unirnark Corporation San Ramon, Calif.

Primary Examiner-Edgar S. Burr Au0meyB0yken, Mohler, Foster & Schwab (54] STRIPING MACHINE ABSTRACT: An electrostatic continuous printer having a staply and powder feed means 4 Claims, 6 Drawing Figs.

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printed upon for conducting the powder onto said material.

Patented June 1, 1971 4 Sheets-Sheet 2 Y E K RK mw ww Patented June 1, 1971 4 Sheets-Shet 3 Q m "a Mam/N 4. Juana? 3/ Arrow/5K5 Patented June 1, 1971 4 Sheets-Sheet 4 //v VENTOP Mun/v flit/wall? M firroewEK;

STRIPING MACHINE BACKGROUND OF INVENTION The present invention is similar, generally, to the inventions disclosed in the U.S. Pat. No. 3,081,698 of Mar. 19, I963, to Childress et al., and D. S. Londahl et al., US Pat. No. 3,352,234 of Nov. 14,1967.

In the present invention, rotatably supported screens are deleted, together with the relatively complicated mountings, drive connections and other means for correlating the rotary screens to a powder supply and powder feeding means. Instead, the printing screen and the supply of printing powder are stationary and the printing powder is fed from the powder supply to a rotary element, in a predetermined amount that can be varied, and by said element to the screen for being physically urged by the latter into the screen openings and into an electrostatic field that conducts the powder onto the material to be printed upon.

The present invention is adapted to print stripes of different widths, according to the dimension of the area or areas of unobstructed openings in the screen, through which the powder is adapted to be moved.

One application of the present invention is printing within the parallel, spaced grooves in boards to simulate the division of a board into separate panels. Heretofore, this printing of a stripe in each groove has been performed by the application of wet paint, with the result that, in many instances, some paint has run over theboard along opposite sides of the groove, and which paint must be cleaned off as a separate operation, and the paint is susceptible to running after being applied, and in other instances, the wet paint is not applied evenly.

The present disclosure also shows apparatus adapted to readily apply stripes in adjoining, or overlapping relation as well as being spaced apart any desired distance, or a wide stripe may cover the entire width of a board with other stripes printed thereon.

Other objects and advantages will appear in the description and in the drawings, including improved means for quickly connecting and disconnecting printing heads in a combination employing several, and an improved structure and arrangement for replenishing the powder supply and for separating the printing screen and feeder from the supply of powder to obtain access to the screen and to the means for urging the powder through the screen.

Other objects and advantages will appear in the description and in the drawings.

DESCRIPTION OF DRAWINGS FIG. 1 is an isometric view of the printer;

FIG. 2 is an enlarged cross-sectional view taken substantially along line 2-2 of FIG. I, the conveyor drive and article support being semidiagrammatically shown;

FIG. 3 is a still greater enlarged cross-sectional view taken through one of the powder feed mechanisms and stencil screens substantially along line 3-3 of FIG. 1;

FIG. 4 is an end elevational view of one of the elements of the printer, with the powder supply portion partly broken away and in cross section;

FIG. 5 is a fragmentary, reduced size bottom plan viewof a stencil screen showing the obstruction-free portions of the screens for a relatively narrow stripe;

FIG. 6 is a modified form of the screen shown in FIG. 5 that is adapted to print a wider portion without enlarging the unobstructed portion of the screen.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A horizontally disposed frame, generally designated 1, (FIGS. 1, 2) comprises a pair of equally spaced, horizontally elongated end frame members, generally designated 2, and a horizontally extending central frame member, generally designated 3, midway between frame members 2. The frame members 2, 3 are parallel and in side-by'side relation, and are connected at their ends by cross frame members 4.

Each of the end frame members 2 may comprise a pair of channel strips 5 welded together one above the other with their webs or bottom portions horizontal and together to form a single frame member of substantially H-shape in cross-sec tional contour with open opposite top and bottom sides, and having lateral sides terminating in intumed marginal portions 6 (FIG. 3).

The central frame member 3 may comprise two pairs of channel members 7 formed in the same manner as each end frame member, and secured together so that the upper side of the central frame member 3 provides a pair of upwardly opening slots 8 extending longitudinally of said central frame member 3 and disposed between inturned marginal portions 9 that correspond to marginal portions 6 of the channel strips or members 5 of the side frame members 2.

Extending at their ends across the upper open side of each frame member 2, and across the open upper side of the central frame portion 3 nearest thereto are horizontally disposed plates 10.

A plate I3 (FIGS. 1, 3, 4) is disposed between the end portion of each plate I0 and each side frame member 2, which plate I3 is adjustably secured to each side frame member by bolts I4 that extend through plates 13 and the open upper side of each frame member 2 and that are threadedly connected at their lower ends in clamping nuts I5 that extend across and below the inturned portions 6 of said side frame members (FIG. 3).

The ends of each plate 10 are, in turn, releasably secured to plates 13 by a conventional quick releasable stud and receptacle 16 (FIG. 4). 1

Each plate 10 is formed with a pair of spaced circular openings 17 (FIG. 3) in alignment longitudinally of each plate 10, and supported on each plate 10 is powder housing 18 that is elongated longitudinally of said plate, having an open lower side over said openings 17. Said housing has outwardly projecting flanges I9 at its opposite ends that are releasably secured to plate 10 outwardly of openings 17 by quick releasable bolts 20, the latter being of a type similar to the studs and receptacles 16.

Parallel positioning strips 23 are respectively secured by screws 24 on each plate I0 in positions extending along the free edges of the end flanges 19 of each housing 18, thus positioning the housing between said strips.

Each housing 18 is rectangular in horizontal cross-sectional contour, and the lowermost portion 25 carrying flanges 19 is horizontally enlarged to provide an enlarged chamber in the lower part of the housing having an upper wall 26 (FIG. 3).

Secured by bolts 27 against and below the upper wall 26 of the enlarged lower portion of each housing 18 are correspondingly marginal portions of an upper plate 28 and a lower plate 29 having a pair of corresponding openings 30 disposed over openings 17 in plate 10, with a web 33 extending on each plate 28, 29 between said pair of openings 30.

Sandwiched between said pair of plates 28, 29 is a planar screen of inelastic material 34 that extends across openings 30 and between the marginal portions of said plates 28, 29 and webs 33, and belowsaid screen is a sheet 35 of rubberlike soft resilient filter material known to the trade as Scott Foam. This sheet 35 extends across openings-30 and is compressed and held at its marginal portions and central portion between the plates 28, 29 and webs 33 and the wall 26 by said bolts 27. This sheet 35 provides a plurality of closely adjacent, generally vertically extending differently tortuous passageways having open upper and lower ends, which passageways and open ends are of a sufficient size to freely pass particles of printing powder supported on said screen 34 therethrough, but the walls of the passageway obstruct free vertical falling unless shocks are administered to the sheet so as to cause the particles to follow the tortuous passageways. Said passageways and open ends thereof are substantially uniform in number, hence the powder that falls from the lower open ends of the passageways is in a uniform layer. The degree and frequency of the shocks transmitted to the sheet 35, and

consequently to the walls of the passageways through the sheet may readily be adjusted to cause a highly accurate metering of the powder as to amount per minute, without turbulence of the powder such as would be caused by use of air to agitate the powder. The perforations of screen 34, which may be of mesh of perforated material, are sufficiently large to freely pass powder therethrough, and as the screen in inelastic it is not distorted by the weight of powder thereabove.

Spaced above screen 34 in each housing are a pair of superposed corrugated sheets 36, 37, sheet 36 being lowermost. The corrugations 38 in said sheets are parallel, uniform, and extend transversely of the length of the housing 18, and project upwardly from the plane of each sheet. Said corrugations 38 are spaced apart in sideby-side relation and are hemispherical at their uppermost portions in cross-sectional contour. The marginal portions 39 of the planar sheets from which the corrugations are formed, remain planar at the opposite ends of the rows of corrugations of each sheet (FIG. 3). The coplanar portions of sheets 36, 37 that are disposed between adjacent pairs of corrugations are slotted out to provide slots 43 that extend longitudinally of said corrugations 38 and partly up the sides of the latter, said slots terminating slightly short of the ends of said corrugations so that planar portions 40 of the upper sheet of the pair will be supported at the ends of the corrugations of said upper sheet on the upper surfaces of the end portions of the corrugations 38 of the lower sheet (FIG. 4).

Sheets 36, 37 are identical, and the aforesaid coplanar end portions 40 have extensions or flanges 44 (FIG. 4) that project divergcntly downwardly along opposite side edges of the sheets 36, 37, so that extensions 44 of the lowermost sheet 36 will be supported on the marginal portions of upper plate 28 while the extension 44 of the uppermost sheet 37 of each pair will extend downwardly over and in engagement with the extensions 44 of the lowermost sheet. Thus, the lower sheet 36 is nested within the upper sheet 37, and the ends of the corrugations are closed.

By end-to-end reversal of the upper sheet relative to the lower sheet, the corrugations 38 of sheet 36 are in staggered relation to the corrugations of sheet 37, and the planar end portions 40 of the upper sheet 37 will still be supported on the upper surfaces of the end portions of the corrugations 38 of the lowermost sheet 36 (FIG. 3).

Housing 18 has a removable cover 45 and a body of printing powder may be deposited in the housing 18, which body will be partially supported on the corrugated sheets 36, 37 but will be shaken through slots 43 to screen 34 upon agitation of the screen and sheet 36. By this arrangement, the major weight of the body of powder within housing 18 may be supported on sheets 36, and packing of the powder on screen 34 will be obviated.

Obviously, the housings 18 may be of any desired height, and for long printing runs they are preferably substantially higher.

Bolted to the upper wall 26 of each housing 18 that is adjacent to the central frame member 3, and projecting toward, but at a level above, each member 3, by bolts 46, is a horizontal plate 47, which may be called an anvil plate.

Below each plate is a horizontally elongated housing generally designated 48 having an open upper side, and outwardly extending flanges 49 along the upper edges of its longitudinally extending sides (FIG. 3) and a horizontal bar 50 secured below each flange carries receptacles 53 (FIG. 3) for conventional quick release stud bolts 54 that extend through openings in plate 10 for releasably securing each housing 48 to and against plate 10.

Each housing 48 has opposite end walls 55, 56, the wall 55 being at the end of the housing nearest the central frame member 3. The opposite end wall 56 of each housing is closed, and each end wall supports a ball bearing 57 therein for rotatably supporting a horizontal shaft 58; which shaft extends through an opening in wall 55 and projects outwardly therefrom.

The bottom wall 59 of each housing 48 is centrally formed with a transversely extending upwardly projecting rib 60 having divergcntly downwardly slanted sides (FIG. 3).

A horizontally disposed roller 63 (FIG. 3) is secured on shaft 58 at opposite sides of each rib 60, the outer layer 64 of each roller being relatively thick and of the aforementioned Scott Foam.

Rollers 63 are respectively in vertical register with openings 30 in plate 10 and said openings are of sufficient diameters to expose the rollers 63 to powder shaken through the uncompressed portions of sheet 35 that are above and that extend across the openings 30, so that powder falling from the sheet 35 will be deposited on the rollers 63.

The bottom wall 59 of housing 48 is formed with a pair of openings 65 that are elongated and in alignment longitudinally of the housing 48, and at opposite sides of the rib 60. A horizontal planar stencil screen 66 is below housing 48 and extends across each opening 65 with its marginal portions secured to the lower side of the bottom wall 59 of each housing and each opening. Each stencil screen may be of electrically conductive sheet material formed with perforations which have been stopped out with the exception of an elongated portion 67 (FIG. 5) positioned centrally with respect to the opening 65, and which portion 67 extends longitudinally of the housing 48. Alternatively, the area 68 (FIG. 6) of unobstructed perforations of each screen may be inclined relative to the length of the housing.

In either instance the lower surface of each roller 63 will move the powder deposited thereon through the unobstructed openings, upon rotation of the rollers, and the outer layers of the rollers will preferably cover the screens and will force the powder through the perforations.

Each set of housings I8, 48 comprises a printing unit, and the apparatus shown in FIG. I is adapted to print stripes on a sheet of material 70, and which stripes are restricted to area within upwardly opening grooves 71 in said sheet material. These sheets may be standard 4X8 panels with the grooves extending lengthwise of the latter, and by the present structure any desired spacing between stripes may be obtained. Rollers 73, in a row of any desired length extending to and away from opposite sides of the printing apparatus may support the sheets 70 for movement past and below sets of housings providing the printing units, in a direction normal to the rows of housing sets along opposite sides of the central frame member 3. One of the rollers 73 adjacent each of the opposite sides of the apparatus (FIG. 2) may be driven through belt or chain connections 74 with a pulley driven by a motor 75, and conventional downwardly yieldable holddown rollers 76 may be over the driven rollers 73 to hold any warped sheets planar during passage below the printing units.

An angle plate 77 (FIGS. 1, 3) having a horizontal leg 78 and a vertical leg 79 depending from one edge thereof is positioned opposite to each printing unit on the curved frame member 3 below the end portion of each plate 10 that carries the housings of each printing unit, the leg 78 of each plate 77 being between plate 10 and the portion of frame member 3 nearest to the printing unit that is opposite thereto and extending over the upwardly opening slot 8 (FIG. 3). The leg 78 is adjustably secured to the central frame member 3 by bolts 80 that extend therethrough and through slot 8 for threaded engagement with a nut 81 that, in turn, engages the inturned marginal portions 9 at opposite sides of the slot, while a conventional quick release bolt 82 and receptacle, corresponding to the bolt and receptacle 16 at the opposite end of the plate 10 releasably secures the plate 10 to the leg 78.

The other leg 79 of each angle plate 77 is in spaced opposed relation to the lower housing 48 of the printing unit on plate I0 and rotatably carries a combined sprocket wheel 84 and coupling element 85 that are coaxial with the shaft 58, carrying rollers or brushes 63 (FIG. 3). The coupling element 85 is provided with a pair of spaced projections 86 at opposite sides of the axis of rotation of the sprocket-coupling combination, which projections extend axially of the coupling element 85 toward the lower housing of the printing unit opposite thereto.

The end of shaft 58 of each printing unit that projects toward the couplingelement 85 opposite thereto is provided with a coupling member 87 (FlG. 3) that is coaxial with said shaft and that is disposed between projections 86 and shaft 58, which coupling member 87 is provided with a crossbar 88 extending between projections 86, and transversely across the axis of shaft 58 whereby upon rotation of the sprocketcoupling combination the projections 86 will be engaged by the crossbar for rotating shaft 58 and rollers 63.

The sprocket wheels 84 along each of the opposite sides of the central frame member 3 are driven in the same direction by a pair of corresponding sprocket chains 89, one extending along each side of the frame member 3 and over sprocket wheels 90 (FIG. 1) at opposite sides of one end of frame member 3, and corresponding sprocket wheels at the opposite end of said frame member, only one being shown in FlG. 1, but in each instance the pairs of sprocket wheels at each end are coaxial on shafts carried by a longitudinal extension 93 of frame member 3 at one end of the latter, and on the vertical legs 79 of angle plates 77 adjustably secured on the frame member 3 at the opposite end of the latter, so that the chains may be maintained tight by adjustment of the last-mentioned plates 77 longitudinally of said frame member 3.

The lower run of each chain 89 extends over the sprocket wheels 84 and between guide pieces 91 (P16. 3) on the central member 3 that, in turn, are between the upper and lower runs of each chain 89, and that are grooved to slidably retain the links of said chains. A second sprocket wheel 92 is on one of the shafts on extension 93 and a chain 94 connects said second wheel with a sprocket wheel driven by motor 95 for driving all of the sprocket wheels in one direction.

A pair of corresponding, upstanding brackets 96 are respectively secured on each end of the central frame member 3, and a horizontal shaft 97 is rotatably supported at its ends in bearings carried by the upper end portions of said brackets.

A channel strip 98, corresponding to the lower channel strip 5 of each side frame member 2, extends longitudinally of shaft 97 thereabove with the open side of the channel strip facing said shaft, and pieces 99 are adjustably secured to said chan- *nel strip, but below the later, by bolts and nuts corresponding to bolts 14 and nuts 15. These pieces 99 have a forked lower end portion that straddles the shaft 99 to prevent lateral springing of the shaft intermediate its ends, inasmuch as said a shaft carriesstrikers that intermittently and laterally strike the ends of the anvil plates 47.

Each of arms 102 (FIG. 3) is split at its upper end and clamped to. shaft'97 by a clamping bolt 103 extending across the split, and the lower end portion of each arm below shaft 97 is divided to receive therebetween the upper vertically extending end portion 104 of laterally projecting striker 105 that, in turn, is spaced below each arm 102. Portion 104 of each striker is pivotally supported between the lower end portions of each arm 102 by a horizontal pivot 106 that is intermediate the upper and lower ends of the vertically extending portion of said striker.

Each arm 102 is clamped to shaft 97 in a position opposite each printing unit and the striker 105 is directed toward the printing unit and is spaced opposite to each anvil plate on each unit. Thus the strikers for the printing units along one side of the frame member 3 will be directed toward the anvil plates 47 of said units while the strikers on the arms 102 that are opposite to the printing units on the opposite side of frame member 3 will be directed in an opposite direction. Upon oscillatory movement of the shaft 97 about its axis from a neutral position, the strikers on said shaft will quickly strike the anvil plates 47 along one side of the frame member 3 and will then strike the anvil plates 47 at the opposite side of said frame member.

Spaced above each pivot 106 is a generally horizontally disposed U-shaped member 107 having legs extending across opposite sides of the divided lower end portion of each arm 102, and the outer ends of said legs are secured to the arms by .a pin 108 against which the lateral edge of the upper end of portion 104 of the striker is adapted to engage to act as a stop for limiting the swinging of the strikers in one direction about pivot 106, while the closed end of the U-member 107 threadedly carries an adjusting bolt 109 for movement of the latter toward and away from the portion 104. A spring 110 is disposed between the bolt 109 and the upper end of portion 104, which spring is at the same side of portion 104 as the side to which the striker 105 projects.

By the above structure, the degree of shock transmitted to each anvil plate by each striker may be determined by the tension of spring 110, and also by the adjustment of each arm 102 on shaft 97.

An arm 113 (FIG. 1) is secured at one end thereof to one end of shaft 97, and the opposite end of said arm is pivotally connected by a link 114 to the end ofa plunger rod 115 having a piston reciprocable within a double acting air cylinder 116 carried by the frame of the machine.

Upon reciprocation of the rod 115 by alternate admission and discharge of air into the ends of the cylinder from a suitable source of air under pressure, the striker 105 will be actuated to alternately strike the anvils 47 of the pair of rows of housings 18 at a frequency that will effect a uniform discharge of powder through stencil screens 66 to print a uniform continuous stripe.

A solenoid actuated valve 117 in the air lines between the source of air under pressure and the cylinder 116 may be actuated by a variable speed motor 1 18 to effect reciprocation of the rod 115 and subsequent oscillation of arm 113 and shaft 97, and the frequency of the oscillations may be controlled by the speed of the motor, the latter being operably connected with the valve actuating means through cam means 119 and reduction gears, and switches in the circuit with the solenoids. The solenoid valve units including the switches, motor and cam means are conventional, although it is to be understood that any other equivalent means may be employed for oscillating the shaft 97.

The stencil screens 66 are of electrical conductive material electrically insulated from the remainder of the housing, or housing 48 itself may be of nonconductive plastic or other nonconductive material.

A source of potential 120 is connected between each of screens 66 and ground, it being understood that the screens 66 may be connected, if desired, and an electrically conductive stationary plate 121 extending below the portion of the material 70 below said screens is grounded so that an electrostatic field is established between the screens and said plate for conducting the printing powder urged through saidscreens onto the material 70 and such powder will only be deposited in the grooves 71 where the width of the unobstructed portion 67 (FIG. 5) is substantially the width of the grooves and where said portions are parallel with said grooves.

ln printing continuous stripes, or any continuous coating, it is desirable that the screen remain stationary and that the exposed or unobstructed portion 67 be relatively long and equidistant from the material being printed upon for the full length of the portion or portions 67. The rollers 63 rotate about axes extending longitudinally of the path of travel of the material 70 so that the full length of each portion 66 of the screen engages a roller.

[n the present machine, the bottom 59 of each housing 48 is formed with a cross-rib 60 for increasing the rigidity of the bottom 59, and also shortening the length of each roller on each shaft 58 and retaining any surplus powder falling through each opening 17 in plate 10 at the sides of the rib 60 below said openings.

The fact that each printing unit may be quickly adjusted as a unit longitudinally of the frame members 2, 3 and'quickly and accurately secured in adjusted position, is of importance, as is the structure in which the upper and lower housings 18, 48 may be quickly removed from plate 10 and resecured thereto in a matter of seconds.

The provision of supporting separate printing units at dif ferent positions longitudinally of the material to be printed upon, enables the printing of separate stripes that may be arranged anywhere from superposed relation through partial overlapping relation to different spaced relationships or to uniformly spaced positions, and as certain printing units may be quickly removed from the machine, it is clear that any desired number of stripes may be printed.

It is also pertinent to note that anvils or anvil plates 47 have longitudinally extending and edges engageable at different points therealong by the strikers 105, which enables the printing units in the pair'of rows to be positioned so that the printing powder dispersed from the units of each pair may be from said superposed relation to any desired spacing, or to producing narrow or wide stripes or a combination of narrow and wide stripes, without the addition of other printing units.

The movement of boards 70 past the printing stations is continuous and the surface speed may be regulated to provide the desired thickness of the coating.

Each set of superposed housings 18, 48, including the elements in each housing, comprises a printing head or unit, and the quick removal of the lower housing 48 enables rapid substitution ofdifferent width screens, while the double row of printing units, and their adjustment to any position relative to each other longitudinally of each row, along the frame, not only enables a difference in spacing of stripes and different width stripes, but enables a continuous coating. Thus the printing units of the pair of rows may be in echelon or tandom relation, and to any offset degree or degrees if in echelon ar rangement.

The plates 10 supporting each printing unit, being adapted to be positioned on or secured from the frame while carrying each printing head, and a similar quick positioning or removal of each striker assembly enables adding or removal of any number of printing heads, within the capacity of the frame, and the automatic coupling and uncoupling of the shafts 58 of each brush with a motor driven coupling member 85 carried on each of the angle plates 77 carrying each striker I05, facilitates the quick addition and substitution and adjustment of the printing units and strikers.

[t is obvious that those skilled in the art may vary the details of construction and arrangement of parts without departing from the spirit of this invention and therefore it is desired not to be limited to the exact foregoing disclosure except as may be demanded by the claims.

lclaim:

1. An electrostatic printer for printing a continuous stripe on an article moved therepast comprising:

a. an upper housing having a horizontally disposed porous support secured thereto for supporting thereon a supply of dry printing powder of sufficient fineness to pass through said support for dropping therefrom upon shocks being administered to said upper housing for transmission to said support and shock-administering means actuatable for intermittent movement into sharp engagement with said housing for so administering said shocks,

b. means supporting said shock-administering means in a position for engaging said upper housing upon actuation of said shock-administering means, and means operatively connected with said shock-administering means for actuating the latter,

c. a lower housing below said upper housing secured to said upper housing having an open upper side aligned below said porous support for passage of powder dropped from said support into said lower housing, and a bottom in said lower housing including a horizontally disposed stencil screen for receiving thereon powder dropping through the open upper end of said lower housing from said porous support, said screen having a group of unobstructed openings thereon for passing therethrough powder received from said support,

d. a frame supporting said upper and said lower housing stationary thereon relative thereto and to each other,

. conveyor means for supporting the article to be printed upon in a position spaced below said screen with a portion thereof in opposed relation to said screen for continuous movement of said article horizontally past said screen in one direction, uniformly spaced from said screen when said conveyor is actuated and when such article is on said conveyor means, and means connected with said conveyor means for actuating the latter for continuously so moving said conveyor means past said screen, said frame supporting said upper and lower housing stationary relative to said conveyor means,

. means for establishing a continuous electrostatic field between said screen and the portion of said article in spaced opposed relation to said screen during continuous movement of said conveyor means and article past said screen and during actuation of said shock-administering means when said article is on said conveyor means,

g. powder moving means 'in said lower housing in engagement with said screen and with powder dropped from said porous support actuatable for continuous movement relative to said screen for continuously forcing powder dropped from said support through said group of openings in said screen into the electrostatic field established between said portion of said article andsaid screen for conduction in said field onto said article, and actuating means connected with said powder moving means for actuating the latter for said continuous movement thereof, whereby a continuous stripe of said powder of a width no greater than the width of said group of openings in a direction transversely of said direction of movement will be deposited on on said article.

2. In an electrostatic printer as defined in claim 1;

h. said group of openings being elongated and extending longitudinally of the direction of movement of said article, and

i. means for fixing onto said article the powder so conducted onto said article.

. In an electrostatic printer as defined in claim 2;

said powder moving means comprising a horizontally elongated brush extending longitudinally of said screen and parallel with said direction of movement of said conveyor means and article and a shaft extending longitudinally of said brush supporting the latter for continuous rotation about the axis of said shaft, said brush being in engagement with said screen over the length and width of said group of openings and said actuating means for said powder moving means being connected with said shaft.

4. An electrostatic printer for printing a continuous stripe comprising:

a. an upper housing having a horizontally disposed porous support secured thereto for supporting thereon a supply of dry printing powder of sufficient fineness to pass through said support for dropping therefrom upon shocks being administered to said upper housing for transmission to said support and shock-administering means actuatable for intermittent movement into sharp engagement with said housing for so administering said shocks,

b. means supporting said shock-administering means in a position for engaging said upper housing upon actuation of said shock-administering means, and means operatively connected with said shock-engaging means for actuating the latter,

. a lower housing below said upper housing secured to said upper housing having an open upper side aligned below said porous support for passage of powder dropped from said support into said lower housing, and a bottom in said lower housing including a horizontally disposed stencil screen for receiving thereon powder dropping through the open upper end of said lower housing from said porous support, said screen having a group of unobstructed openings thereon for passing therethrough powder received from said support,

d. a frame supporting said upper and said lower housing stationary thereon relative thereto and to each other,

e. conveyor means for supporting the article to be printed upon in a position spaced below said screen in opposed means for establishing a continuous electrostatic field between said screen and the portion of said article in spaced opposed relation to said screen during actuation of said conveyor means and continuous movement of said article past said screen and during actuation of said shock-administering means, and said conveyor means when such article is on said conveyor means,

. powder moving means in said lower housing in engagement with said screen and with powder dropped from said porous support actuatable for continuous movement relative to said screen for continuously forcing powder dropped from said support through said group of openings in 'said screen into the electrostatic field established between said portion of said article and said screen for conduction in said field onto said article, and actuating means connected with said powder moving means for actuating the latter for said continuous movement thereof, whereby a continuous stripe of said powder of a width no greater than the width of said group of openings in a direction transversely of said direction of movement will be deposited on said article,

. a pair of plates disposed one above the other in vertically spaced relation within said upper housing spaced above said porous support for supporting a body of said powder thereon,

i. the plates of said pair being formed with openings for free passage of powder therethrough with the openings in the upper of said plates in staggered relation to the openings in the lower plate to relieve said porous support from carrying the full weight of said body,

'. said shock-administering means including an anvil connected with said upper housing, and a striker adjacent thereto supported for intermittent movement into engagement with said anvil, and

. means connected with said striker for so moving the latter into said engagement with said anvil. 

1. An electrostatic printer for printing a continuous stripe on an article moved therepast comprising: a. an upper housing having a horizontally disposed porous support secured thereto for supporting thereon a supply of dry printing powder of sufficient fineness to pass through said support for dropping therefrom upon shocks being administered to said upper housing for transmission to said support and shock-administering means actuatable for intermittent movement into sharp engagement with said housing for so administering said shocks, b. means supporting said shock-administering means in a position for engaging said upper housing upon actuation of said shockadministering means, and means operatively connected with said shock-administering means for actuating the latter, c. a lower housing below said upper housing secured to said upper housing having an open upper side aligned below said porous support for passage of powder dropped from said support into said lower housing, and a bottom in said lower housing including a horizontally disposed stencil screen for receiving thereon powder dropping through the open upper end of said lower housing from said porous support, said screen having a group of unobstructed openings thereon for passing therethrough powder received from said support, d. a frame supporting said upper and said lower housing stationary thereon relative thereto and to each other, e. conveyor means for supporting the article to be printed upon in a position spaced below said screen with a portion thereof in opposed relation to said screen for continuous movement of said article horizontally past said screen in one direction, uniformly spaced from said screen when said conveyor is actuated and when such article is on said conveyor means, and means connected with said conveyor means for actuating the latter for continuously so moving said conveyor means past said screen, said frame supporting said upper and lower housing stationary relative to said conveyor means, f. means for establishing a continuous electrostatic field between said screen and the portion of said article in spaced opposed relation to said screen during continuous movement of said conveyor means and article past said screen and during actuation of said shock-administering means when said article is on said conveyor means, g. powder moving means in said lower housing in engagement with said screen and with powder dropped from said porous support actuatable for continuous movement relative to said screen for continuously forcing powder dropped from said support through said group of openings in said screen into the electrostatic field established between said portion of said article and said screen for conduction in said field onto said article, and actuating means connected with said powder moving means for actuating the latter for said continuous movement thereof, whereby a continuous stripe of said powder of a width no greater than the width of said group of openings in a direction transversely of said direction of movement will be deposited on on said article.
 2. In an electrostatic printer as defined in claim 1; h. said group of openings being elongated and extending longitudinally of the direction of movement of said article, and i. means for fixing onto said article the powder so conducted onto said article.
 3. In an electrostatic printer as defined in claim 2; j. said powder moving means comprising a horizontally elongated brush extending longitudinally of said screen and parallel with said direction of movement of said conveyor means and article and a shaft extending longitudinally of said brush supporting the latter for continuous rotation about the axis of said sHaft, said brush being in engagement with said screen over the length and width of said group of openings and said actuating means for said powder moving means being connected with said shaft.
 4. An electrostatic printer for printing a continuous stripe comprising: a. an upper housing having a horizontally disposed porous support secured thereto for supporting thereon a supply of dry printing powder of sufficient fineness to pass through said support for dropping therefrom upon shocks being administered to said upper housing for transmission to said support and shock-administering means actuatable for intermittent movement into sharp engagement with said housing for so administering said shocks, b. means supporting said shock-administering means in a position for engaging said upper housing upon actuation of said shock-administering means, and means operatively connected with said shock-engaging means for actuating the latter, c. a lower housing below said upper housing secured to said upper housing having an open upper side aligned below said porous support for passage of powder dropped from said support into said lower housing, and a bottom in said lower housing including a horizontally disposed stencil screen for receiving thereon powder dropping through the open upper end of said lower housing from said porous support, said screen having a group of unobstructed openings thereon for passing therethrough powder received from said support, d. a frame supporting said upper and said lower housing stationary thereon relative thereto and to each other, e. conveyor means for supporting the article to be printed upon in a position spaced below said screen in opposed relation to said screen for continuous movement of said article horizontally past said screen in one direction uniformly spaced from said screen when said conveyor is actuated for continuous movement in said one direction and when such article is on said conveyor means, and means connected with said conveyor means for actuating the latter for continuously so moving said article past said screen, said frame supporting said upper and lower housing stationary relative to said conveyor means, f. means for establishing a continuous electrostatic field between said screen and the portion of said article in spaced opposed relation to said screen during actuation of said conveyor means and continuous movement of said article past said screen and during actuation of said shock-administering means, and said conveyor means when such article is on said conveyor means, g. powder moving means in said lower housing in engagement with said screen and with powder dropped from said porous support actuatable for continuous movement relative to said screen for continuously forcing powder dropped from said support through said group of openings in said screen into the electrostatic field established between said portion of said article and said screen for conduction in said field onto said article, and actuating means connected with said powder moving means for actuating the latter for said continuous movement thereof, whereby a continuous stripe of said powder of a width no greater than the width of said group of openings in a direction transversely of said direction of movement will be deposited on said article, h. a pair of plates disposed one above the other in vertically spaced relation within said upper housing spaced above said porous support for supporting a body of said powder thereon, i. the plates of said pair being formed with openings for free passage of powder therethrough with the openings in the upper of said plates in staggered relation to the openings in the lower plate to relieve said porous support from carrying the full weight of said body, j. said shock-administering means including an anvil connected with said upper housing, and a striker adjacent thereto supported for intermittent movement into engagement with said anvil, and k. means connected with said strIker for so moving the latter into said engagement with said anvil. 